The Ubermensch is Friedrich Nietzsche's answer to the problem of Nihilism. Nietzsche begins his premise with the assumption that God does not exist, and if God does not exist, thus objective morality and inherent value are not possible since there is no ultimate being that exists to create morality and value in the first place.
Nietzsche's Ubermensch will act as his own God, giving himself morality and value as he sees fit according to him alone. The Ubermensch is neither slave or master as he does not impose his will upon others. The Ubermensch is an independent individual who has the power to banish herd instincts from his mind and become a master of self discipline.

Above all, the Ubermensch is the next step in human evolution. Every human must deal with the question "What is the meaning of life"- some say God and Heaven, others say ultimate objective virtue, but the Ubermensch will give life value that is not based on superstition or mystical folly. The Ubermensch finds value in his life experience because it cannot be reasoned out through argument and logic. The Ubermensch would say that the meaning of life is that you die, so make it valuable.

The Ubermensch is the opposite of Jesus Christ.

The Ubermensch is the ultimate realization of the Will to Power, but no necessarily over others. His most valuable power is over himself. "He cannot rule himself will certainty be ruled by others"- Nietzsche

The overman, for Nietzsche, did not and could not exist as a contemporary, since he saw himself as living in decadent times incapable of spawning ones who were capable of "standing security for their own destiny." Personally, i would suggest that the Overman would be one who could bear the horror of memory and cognizance of the present while simultaneously retaining the vigor and purpose of those who Nietzsche describes as nobles in "The Genealogy of Morals."

Examples are not helpful. German foot soldiers in WWI carried copies of "Thus Spake Zarathustra." The twentieth century bears witness to the idiocy of Nietzsche interpreters...

an adjective used to describe a person who is awesome, talented, cool, hip, or someone who did something excellent. It came from Friedrich Nietzsche's vision of an ideal Man who was able to achieve self-actualization, and has developed himself holistically.

Like the afore stated it was introduced by Nietzsche in his book Thus Spake Zarathustra to simplify of course the ubermensch in modern terms would be one who is self actualized and spreads his influence to those around him